Precision synchronization may be used in a packet network to distribute timing from a producer to a consumer. The producer and consumer may or may not communicate through the packet network. There are many different efforts to better synchronize the local clocks of nodes on different networks. Better timing and better synchronization provide many different benefits.
One approach to synchronizing the clocks or nodes of a packet data network is referred to as PTP (Precise Time Protocol), and is defined in IEEE-1588 2008, IEEE (Institute of Electrical and Electronics Engineers) Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems. The PTP approach is intended to provide precise clock timing synchronization over a packet network. In brief, PTP distributes a grandmaster clock's time of day to a large number of slave clocks using special PTP messages. The PTP packets include timestamps. A slave clock receives the included timestamp and then adjusts its local clock to track and recover the timing of the master clock from which it received the timestamp. This delay may include the time required for the PTP packet to travel from the master clock to the slave clock.
The slave clock may serve as a master to another clock. This chain from master to slave through a sequence of clocks allows PTP to align each slave clock to the grandmaster clock to within less than a microsecond.